scholarly journals Monapinone Coupling Enzyme Produces Non-Natural Heterodimers

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1015
Author(s):  
Satoshi Ohte ◽  
Masayuki Toyoda ◽  
Keisuke Kobayashi ◽  
Isao Fujii ◽  
Taichi Ohshiro ◽  
...  

The monapinone coupling enzyme (MCE), a fungal multicopper oxidase, catalyzes the regioselective C–C coupling between tricyclic monapinone A (the primary substrate) and other monapinones (secondary substrates) to produce atropisomeric biaryl homo- or heterodimers. In this study, mono-, bi- and tricyclic compounds were tested to determine whether they worked as secondary substrates for MCE. Among 14 cyclic compounds, MCE utilized semivioxanthin, YWA1, 1,3-naphthalenediol and flaviolin as secondary substrates to produce non-natural heterodimers. The atropisomeric biaryl heterodimers produced by MCE from monapinone A and semivioxanthin were isolated, and their structures were elucidated by NMR and MS. These findings indicate that MCE recognizes bi- and tricyclic compounds with a 1,3-dihydroxy or 1-hydroxy-3-methoxy benzene ring as a secondary substrate.

Author(s):  
Jay W. Cha ◽  
Perry J. Melnick

Hereditary ochronosis in very few cases has been examined electron microscopically or histochemically. In this disease homogentisic acid, a normal intermediary of tyrosine metabolism, forms in excessive amounts. This is believed to be due to absence or defective activity of homogentisic acid oxidase, an enzyme system necessary to break the benzene ring and to further break it down to fumaric and acetoacetic acids. Ochronotic pigment, a polymerized form of homogentisic acid, deposits mainly in mesenchymal tissues. There has been a question whether the pigment originates from the collagenous tissues, or deposits passively, where in contrast to melanin it induces degenerative changes.


2019 ◽  
Author(s):  
Chem Int

Coumarin and its derivatives are widely spread in nature. Coumarin goes to agroup as benzopyrones, which consists of a benzene ring connected to a pyronemoiety. Coumarins displayed a broad range of pharmacologically useful profile.Coumarins are considered as a promising group of bioactive compounds thatexhibited a wide range of biological activities like anti-microbial, anti-viral,antiparasitic, anti-helmintic, analgesic, anti-inflammatory, anti-diabetic, anticancer,anti-oxidant, anti-proliferative, anti-convulsant, and antihypertensiveactivities etc. The coumarin compounds have immense interest due to theirdiverse pharmacological properties. In particular, these biological activities makecoumarin compounds more attractive and testing as novel therapeuticcompounds.


2020 ◽  
Vol 5 (443) ◽  
pp. 85-91
Author(s):  
Ibrayev M.K., ◽  
◽  
Takibayeva A.T., ◽  
Fazylov S.D., ◽  
Rakhimberlinova Zh.B., ◽  
...  

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.


1992 ◽  
Vol 25 (11) ◽  
pp. 403-410 ◽  
Author(s):  
B. E. Rittmann

Microbiological detoxification of hazardous organic pollutants is highly promising, but its reliable implementation requires a sophisticated understanding of several different substrate types and how they interact. This paper carefully defines the substrate types and explains how their interactions affect the bacteria's electron and energy flows, information flow, and degradative activity. For example, primary substrates, which are essential for growth and maintenance of the bacteria, also interact with degradation of specific hazardous pollutants by being inducers, inhibitors, and direct or indirect cosubstrates. The target contaminants, which often are secondary substrates, also have the interactive roles of self-inhibitor, inhibitor of primary-substrate utilization, inducer, and a part of an aggregate primary substrate.


1997 ◽  
Vol 36 (6-7) ◽  
pp. 107-115 ◽  
Author(s):  
Gregory J. Wilson ◽  
Amid P. Khodadoust ◽  
Makram T. Suidan ◽  
Richard C. Brenner

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage. Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations. A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.


2018 ◽  
Vol 15 (7) ◽  
pp. 721-732
Author(s):  
Liqiang Meng ◽  
Liqian Sun ◽  
Chaoqun Yan ◽  
Dongxiao Cui ◽  
Jingrun Chen ◽  
...  

Filomat ◽  
2014 ◽  
Vol 28 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Xianyong Li ◽  
Xiaofan Yang ◽  
Guoping Wang ◽  
Rongwei Hu

Spiro hexagonal chains are a subclass of spiro compounds which are an important subclass of Cycloalkynes in Organic Chemistry. This paper addresses general spiro hexagonal chains in which every hexagon represents a benzene ring, and establishes the formulae for computing the Hosoya polynomials of general spiro hexagonal chains.


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